Loader.php

<?php

namespace TheBooking;

defined('ABSPATH') || exit;

if (!class_exists(Loader::class)) {

    /**
     * Class Loader
     *
     * @package TheBooking
     * @author  VonStroheim
     * @since   1.0.0
     */
    final class Loader
    {
        /**
         * The array of actions registered with WordPress.
         *
         * @var      array $actions The actions registered with WordPress to fire when the plugin loads.
         */
        protected $actions;

        /**
         * The array of filters registered with WordPress.
         *
         * @var      array $filters The filters registered with WordPress to fire when the plugin loads.
         */
        protected $filters;

        /**
         * Initialize the collections used to maintain the actions and filters.
         */
        protected function __construct()
        {
            $this->actions = [];
            $this->filters = [];
        }

        /**
         * A utility function that is used to register the actions and hooks into a single collection.
         *
         * @param array         $hooks         The collection of hooks that is being registered (that is, actions or filters).
         * @param string        $hook          The name of the WordPress filter that is being registered.
         * @param object|string $component     A reference to the instance of the object on which the filter is defined, or its name for static method.
         * @param string        $callback      The name of the function definition on the $component.
         * @param int           $priority      The priority at which the function should be fired.
         * @param int           $accepted_args The number of arguments that should be passed to the $callback.
         *
         * @return   array                                  The collection of actions and filters registered with WordPress.
         */
        private function add(array $hooks, $hook, $component, $callback, $priority, $accepted_args)
        {
            $hooks[] = [
                'hook'          => $hook,
                'component'     => $component,
                'callback'      => $callback,
                'priority'      => $priority,
                'accepted_args' => $accepted_args,
            ];

            return $hooks;
        }

        /**
         * Add a new action to the collection to be registered with WordPress.
         *
         * @param string        $hook          The name of the WordPress action that is being registered.
         * @param object|string $component     A reference to the instance of the object on which the action is defined, or its name for static methods.
         * @param string        $callback      The name of the function definition on the $component.
         * @param int           $priority      Optional. he priority at which the function should be fired. Default is 10.
         * @param int           $accepted_args Optional. The number of arguments that should be passed to the $callback. Default is 1.
         */
        public function add_action($hook, $component, $callback, $priority = 10, $accepted_args = 1)
        {
            $this->actions = $this->add($this->actions, $hook, $component, $callback, $priority, $accepted_args);
        }

        /**
         * Add a new filter to the collection to be registered with WordPress.
         *
         * @param string        $hook          The name of the WordPress filter that is being registered.
         * @param object|string $component     A reference to the instance of the object on which the filter is defined, or its name for static methods.
         * @param string        $callback      The name of the function definition on the $component.
         * @param int           $priority      Optional. he priority at which the function should be fired. Default is 10.
         * @param int           $accepted_args Optional. The number of arguments that should be passed to the $callback. Default is 1.
         */
        public function add_filter($hook, $component, $callback, $priority = 10, $accepted_args = 1)
        {
            $this->filters = $this->add($this->filters, $hook, $component, $callback, $priority, $accepted_args);
        }

        /**
         * Register the filters and actions with WordPress.
         */
        public function run()
        {
            foreach ($this->filters as $hook) {
                if (NULL === $hook['component']) {
                    add_filter($hook['hook'], $hook['callback'], $hook['priority'], $hook['accepted_args']);
                } else {
                    add_filter($hook['hook'], [$hook['component'], $hook['callback']], $hook['priority'], $hook['accepted_args']);
                }

            }

            foreach ($this->actions as $hook) {
                if (NULL === $hook['component']) {
                    add_action($hook['hook'], $hook['callback'], $hook['priority'], $hook['accepted_args']);
                } else {
                    add_action($hook['hook'], [$hook['component'], $hook['callback']], $hook['priority'], $hook['accepted_args']);
                }
            }
        }

        /**
         * @return Loader
         */
        public static function instance()
        {
            return new self();
        }
    }
}